CHRONIC HYPOXIA INCREASES BETA-ADRENERGIC-RECEPTOR DENSITY IN THE LUNGS OF YOUNG AND OLD RATS

To test the hypothesis that the ability to regulate beta-adrenergic receptor (BAR) density in response to chronic hypoxic stress is impaired by aging, we measured BAR density in the lungs of young (age 3 months) and aged (age 20 months) rats exposed to hypobaric hypoxia (1/2 atm) for 3 weeks. BAR density increased by 63% in the lungs of both young and aged rats exposed to chronic hypoxia. Lung BAR density was unaffected by aging, independent of hypoxic conditions. We conclude that the ability to respond to chronic hypoxic stress with increased lung BAR density is unaffected by aging in rats.